Is there something wrong with my breast implants? One has suddenly dropped about 1/2 inch lower than the other!

I had my breasts done about 1 and a half years ago with no worries,i absolutely love them! Perfect shape and size and they sit great, BUT the last few months i have noticed the right one has dropped and looks bigger then the left. It is an inch or 1/2 an inch and inch lower then the left, they feel the same and are lovely and soft, except on top like on my chest i can feel the left one is sitting higher and now and the left fills out the bra at the top more than the right? Is this normal?